Sensing circuit of moving body and moving body sensing device

ABSTRACT

A sensing circuit in a device having a moving body in which a unit to be detected including first and second pattern units spaced apart from each other is formed includes an oscillation circuit unit including first and second oscillation circuits fixedly mounted on a substrate spaced apart from the unit to be detected, including, respectively, first and second sensing coils having first and second inductance values depending on areas of overlap between the first and second sensing coils and the first and second pattern units and outputting, respectively, first and second sensed oscillation signals based on the first and second inductance values; and a sensing circuit outputting an output signal having movement information of the moving body based on each period count value for each of the first and second sensed oscillation signals using a reference oscillation signal.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.16/429,170 filed on Jun. 3, 2019 which claims the benefit under 35 USC §119(a) of Korean Patent Application Nos. 10-2018-0145613 filed on Nov.22, 2018, and 10-2019-0029210 filed on Mar. 14, 2019 in the KoreanIntellectual Property Office, the entire disclosure of which areincorporated herein by reference for all purposes.

BACKGROUND 1. Field

The present disclosure relates to a sensing circuit of a moving body anda moving body sensing device.

2. Description of Related Art

In general, a rotating body has been used in various fields such as, forexample, a motor and a wheel switch of a wearable device, which need tobe miniaturized and to have a slim profile. A sensing circuit sensing aposition of the rotating body also needs to sense a fine displacement ofthe rotating body.

A precise signal is needed for a sensing device, where a frequency ishigh and noise such as, jitter, is low, in a sensing manner based on areference oscillation signal. For example, in the sensing device basedon the reference oscillation signal, a manner of sensing rotation of therotating body by measuring a frequency of an input sensed signal using areference clock having a high frequency may be used.

Such a sensing device uses the reference clock having the high frequencyto consume a large amount of power and thus requires a large amount ofpower. In addition, when using one sensing coil to sense the rotatingbody, when noise such as, jitter, is included in a sensed signal of ameasurement target, a sensing error may occur.

In addition, a separate complicated circuit to remove such noise isneeded, a design of the sensing device is complicated, and a cost formanufacturing the sensing device increases.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

According to an aspect there is disclosed a sensing circuit in a devicehaving a moving body in which a unit to be detected including first andsecond pattern units spaced apart from each other is formed, includingan oscillation circuit unit including first and second oscillationcircuits fixedly mounted on a substrate spaced apart from the unit to bedetected, each of the first and second oscillation circuits including,respectively, first and second sensing coils having first and secondinductance values depending on areas of overlap between the first andsecond sensing coils and the first and second pattern units, and thefirst and second oscillation circuits being configured to output,respectively, first and second sensed oscillation signals based on thefirst and second inductance values, and a sensing circuit configured tooutput an output signal having movement information of the moving bodybased on each period count value for each of the first and second sensedoscillation signals using a reference oscillation signal.

The first oscillation circuit may include a first capacitor connected tothe first sensing coil in parallel to contribute LC oscillation and togenerate the first sensed oscillation signal, and the second oscillationcircuit may include a second capacitor connected to the second sensingcoil in parallel to contribute LC oscillation and to generate the secondsensed oscillation signal.

The sensing circuit may include a frequency divider configured to dividea frequency of the reference oscillation signal and to output afrequency-divided reference oscillation signal, a period countingcircuit unit may include first and second period counting circuitsconfigured to generate, respectively, the first and second sensedsignals having first and second period count values counted using thefrequency-divided reference oscillation signal for each of the first andsecond sensed oscillation signals, and a calculation circuit unitconfigured to calculate the first and second sensed signals to generatethe output signal.

The first period counting circuit may include a first period counterconfigured to count a period of the frequency-divided referenceoscillation signal using the first sensed oscillation signal to generatea first period count value for the frequency-divided referenceoscillation signal, and a first filter configured to amplify the firstperiod count value using an accumulated gain to generate a firstamplified period count value and to provide the first amplified periodcount value as the first sensed signal.

The second period counting circuit may include a second period counterconfigured to count a period of the frequency-divided referenceoscillation signal using the second sensed oscillation signal togenerate a second period count value for the frequency-divided referenceoscillation signal, and a second filter configured to amplify the secondperiod count value using an accumulated gain to generate a secondamplified period count value and to provide the second amplified periodcount value as the second sensed signal.

The first and second filters may be configured to determine theaccumulated gain using a preset stage order and a decimator factor.

The first and second filters may be configured to determine theaccumulated gain as a multiplier of the stage order for the decimatorfactor.

The calculation circuit unit may be configured to perform a division onthe first sensed signal and the second sensed signal to generate theoutput signal.

According to another aspect there is disclosed a moving body sensingdevice including a unit to be detected configured to be disposed in amoving body to move based on movement of the moving body and to comprisefirst to N-th pattern units spaced apart from each other, an oscillationcircuit unit including first to N-th oscillation circuits fixedlymounted on a substrate spaced apart from the unit to be detected, eachof first to N-th oscillation circuits including, respectively, first toN-th sensing coils having first to N-th inductance values depending onareas of overlap between the first to N-th sensing coils and the firstto N-th pattern units, and the first to N-th oscillation circuits beingconfigured to output, respectively, first to N-th sensed oscillationsignals based on the first to N-th inductance values, and a sensingcircuit configured to output an output signal having movementinformation of the moving body based on each period count value for eachof the first to N-th sensed oscillation signals using a referenceoscillation signal, wherein N is a natural number of 3 or more.

The first to N-th pattern units may be formed of any one of a metal anda magnetic material having a same shape.

The oscillation circuit unit may include a first oscillation circuit, asecond oscillation circuit, a third oscillation circuit, and a fourthoscillation circuit, the first oscillation circuit may include a firstcapacitor connected to the first sensing coil in parallel to contributeLC oscillation and to generate the first sensed oscillation signal, thesecond oscillation circuit may include a second capacitor connected tothe second sensing coil in parallel to contribute LC oscillation and togenerate the second sensed oscillation signal, the third oscillationcircuit may include a third capacitor connected to the third sensingcoil in parallel to contribute LC oscillation and to generate the thirdsensed oscillation signal, and the fourth oscillation circuit mayinclude a fourth capacitor connected to the fourth sensing coil inparallel to contribute LC oscillation and to generate the fourth sensedoscillation signal.

The sensing circuit may include a frequency divider configured to dividea frequency of the reference oscillation signal and to output afrequency-divided reference oscillation signal, a period countingcircuit unit may include first to fourth period counting circuitsgenerating, respectively, the first to fourth sensed signals havingfirst to fourth period count values counted using the frequency-dividedreference oscillation signal for each of the first to fourth sensedoscillation signals, and a calculation circuit unit configured tocalculate the first to fourth sensed signals to generate first andsecond calculated signals and to output the output signal using thefirst and second calculated signals.

The first to fourth period counting circuits may include, respectively,first to fourth period counters configured to count a period of thefrequency-divided reference oscillation signal using the first to fourthsensed oscillation signals, respectively, to generate the first tofourth period count values for the frequency-divided referenceoscillation signal, and first to fourth filters configured to amplifythe first to fourth period count values using an accumulated gain togenerate first to fourth amplified period count values and to providethe first to fourth amplified period count values as the first to fourthsensed signals.

The first to fourth filters may be configured to determine theaccumulated gain using a preset stage order and a decimator factor.

The first to fourth filters may be configured to determine theaccumulated gain as a multiplier of the stage order for the decimatorfactor.

The calculation circuit unit may include a first calculation circuitconfigured to generate the first calculated signal using the first tofourth sensed signals, a second calculation circuit configured togenerate the second calculated signal using the first to fourth sensedsignals, and a third calculation circuit configured to generate theoutput signal using the first and second calculated signals.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a moving body sensingdevice.

FIG. 2 is a diagram illustrating an example of a moving body sensingdevice.

FIG. 3 is a diagram illustrating an example of a moving body sensingdevice.

FIG. 4 is a diagram illustrating an example of a moving body sensingdevice.

FIG. 5 is a diagram illustrating an example of a sensing circuit of amoving body.

FIG. 6 is a diagram illustrating an example of a sensing circuit of amoving body according to an exemplary embodiment in the presentdisclosure;

FIG. 7 is a diagram illustrating an example of a sensing circuit of amoving body.

FIG. 8 is a diagram illustrating examples of a reference oscillationsignal, a frequency-divided reference oscillation signal, and detectedfirst and second oscillation signals.

FIG. 9 is a diagram illustrating examples of a reference oscillationsignal, a frequency-divided reference oscillation signal, and detectedfirst to third oscillation signals.

FIG. 10 is a diagram illustrating examples of a reference oscillationsignal, a frequency-divided reference oscillation signal, and detectedfirst to fourth oscillation signals.

FIG. 11 is a diagram illustrating an example of a first filter.

FIG. 12 is a diagram illustrating an example of a second filter.

FIG. 13 is a diagram illustrating an example of a third filter.

FIG. 14 is a diagram illustrating an example of a fourth filter.

FIG. 15 is a diagram illustrating an example of a positionalrelationship between a unit to be detected and a sensing coil dependingon rotation of the unit to be detected.

FIG. 16 is a diagram illustrating examples of waveforms of a firstsensed signal and a second sensed signal output from a period countingcircuit.

FIG. 17 are diagrams illustrating examples for describing a positionalrelationship between a unit to be detected and a sensing coil dependingon rotation of the unit to be detected.

FIG. 18 are diagrams illustrating examples of a state relationshipbetween first to fourth sensed signals output from the period countingcircuit, first and second calculated signals, and an output signal;

FIG. 19 is a graph illustrating an example of noise included in anoutput signal of a sensing device.

FIG. 20 is a graph illustrating an example of noise included in anoutput signal of the moving body sensing device.

Throughout the drawings and the detailed description, the same referencenumerals refer to the same elements. The drawings may not be to scale,and the relative size, proportions, and depiction of elements in thedrawings may be exaggerated for clarity, illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known in the art may be omitted forincreased clarity and conciseness.

The features described herein may be embodied in different forms, andare not to be construed as being limited to the examples describedherein. Rather, the examples described herein have been provided merelyto illustrate some of the many possible ways of implementing themethods, apparatuses, and/or systems described herein that will beapparent after an understanding of the disclosure of this application.

Throughout the specification, it will be understood that when anelement, such as a layer, region or wafer (substrate), is referred to asbeing “on,” “connected to,” or “coupled to” another element, it can bedirectly “on,” “connected to,” or “coupled to” the other element orother elements intervening therebetween may be present. When an elementis referred to as being “directly on,” “directly connected to,” or“directly coupled to” another element, there may be no elements orlayers intervening therebetween. Like numerals refer to like elementsthroughout.

The terminology used herein is for describing various examples only, andis not to be used to limit the disclosure. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

The use of the term “may” with respect to an example or embodiment,e.g., as to what an example or embodiment may include or implement,means that at least one example or embodiment exists in which such afeature is included or implemented while all examples and embodimentsare not limited thereto.

It will be apparent that though the terms first, second, third, etc. maybe used herein to describe various members, components, regions, layersand/or sections, these members, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one member, component, region, layer or section fromanother region, layer or section. Thus, a first member, component,region, layer or section discussed below could be termed a secondmember, component, region, layer or section without departing from theteachings of the exemplary embodiments.

Spatially relative terms, such as “above,” “upper,” “below,” and “lower”and the like, may be used herein for ease of description to describe oneelement's relationship to another element(s) as shown in the figures. Itwill be understood that the spatially relative terms are intended toencompass different orientations of the device in use or operation inaddition to the orientation depicted in the figures. For example, if thedevice in the figures is turned over, elements described as “above,” or“upper” other elements would then be oriented “below,” or “lower” theother elements or features. Thus, the term “above” can encompass boththe above and below orientations depending on a particular direction ofthe figures. The device may be otherwise oriented (rotated 90 degrees orat other orientations) and the spatially relative descriptors usedherein may be interpreted accordingly.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”and/or “comprising” when used in this specification, specify thepresence of stated features, integers, steps, operations, members,elements, and/or groups thereof, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,members, elements, and/or groups thereof.

FIG. 1 is a diagram illustrating an example of a moving body sensingdevice.

Referring to FIG. 1, a moving body sensing device may include a unit 20to be detected and a moving body sensing circuit. The moving bodysensing circuit may include an oscillation circuit 100 including asensing element and a sensing circuit 200. The moving body sensingdevice may further include a substrate 300.

In an example, moving body may be a rotating body that is used indevices such as, for example, a smartwatch or a lens moving body used inan actuator of a camera device. The moving body may be used in a devicehaving an object to be detected that moves in order to detect a positionchange on the basis of a change in an impedance or a change in afrequency generated between a magnetic material (or a magnet) and asensing coil with respect to movement. In an example, the moving bodywill hereinafter be assumed to be a rotating body, but is not limitedthereto.

The unit 20 to be detected may be formed in a rotating body 50, and maybe connected to a wheel 10 through a shaft 11 of the rotating body 50.The rotating body 50 may be used in an electronic device, and may berotated clockwise or counterclockwise by a user. The unit 20 to bedetected may rotate clockwise or counterclockwise together with thewheel 10 of the rotating body 50.

The unit 20 to be detected may include a first pattern unit 21 and asecond pattern unit 22. The first pattern unit 21 and the second patternunit 22 may be formed in the same shape, may be spaced apart from eachother by a distance along an extending direction of the shaft 11, andmay be fixedly coupled to the shaft 11. The first pattern unit 21 andthe second pattern unit 22 may be rotated in the same direction and atthe same speed by the shaft of the rotating body 50.

Each of the first pattern unit 21 and the second pattern unit 22 mayinclude at least one pattern having the same shape. The first patternunit 21 may include at least one first pattern, and the second patternunit 22 may include at least one second pattern.

In FIG. 1, protruding areas of the first pattern unit 21 and the secondpattern unit 22 may correspond to the patterns. As an example, at leastone first pattern of the first pattern unit 21 and at least one secondpattern of the second pattern unit 22 may be manufactured by machining adisk-shaped metal or magnetic material to form a sawtooth. In anexample, a first pattern of the first pattern unit 21 and a secondpattern of the second pattern unit 22 may be formed of one of the metaland the magnetic material.

A first pattern of the first pattern unit 21 may extend along a rotationdirection, and a second pattern of the second pattern unit 22 may extendalong the rotation direction. An extending length of the first patternof the first pattern unit 21 in the rotation direction may be defined asa size of the first pattern, and an extending length of the secondpattern of the second pattern unit 22 in the rotation direction may bedefined as a size of the second pattern.

When the first pattern unit 21 includes one first pattern and the secondpattern unit 22 includes one second pattern, one first pattern andsecond pattern may have a size corresponding to a rotation angle of180°.

When it is assumed that the first pattern unit 21 includes a pluralityof first patterns and the second pattern unit 22 includes a plurality ofsecond patterns, the plurality of first patterns of the first patternunit 21 may be arranged to be spaced apart from each other by a distancealong the rotation direction, and the plurality of second patterns ofthe second pattern unit 22 may be arranged to be spaced apart from eachother by a distance along the rotation direction. As an example, aspaced distance between the plurality of first patterns of the firstpattern unit 21 may be the same as a size of the first pattern, and aspaced distance between the plurality of second patterns of the secondpattern unit 22 may be the same as a size of the second pattern.

As an example, the plurality of first patterns of the first pattern unit21 may have a size corresponding to a rotation angle of 90°, and thespaced distance between the plurality of first patterns may correspondto the rotation angle of 90°. Therefore, the first pattern unit 21 mayinclude two first patterns having a size of 90°. Likewise, the pluralityof second patterns of the second pattern unit 22 may have a sizecorresponding to a rotation angle of 90°, and the spaced distancebetween the plurality of second patterns may correspond to the rotationangle of 90°. Therefore, the second pattern unit 22 may include twosecond patterns having a size of 90°.

The sizes and the numbers of first patterns and second patterns may bechanged. As an example, the first pattern unit 21 may include threefirst patterns having a size of 60°, and the second pattern unit 22 mayinclude three second patterns having a size of 60°.

A case in which the first pattern unit 21 includes two first patternshaving a size of 90° and the second pattern unit 22 includes two secondpatterns having a size of 90° will hereinafter be described forconvenience of explanation. However, the following description may beapplied to pattern units including patterns of which sizes correspond tovarious angles and the various numbers.

The plurality of first patterns of the first pattern unit 21 and theplurality of second patterns of the second pattern unit 22 may bearranged to have an angle difference therebetween. As an example, theplurality of first patterns of the first pattern unit 21 and theplurality of second patterns of the second pattern unit 22 may bearranged to have an angle difference corresponding to a half of the sizeof the first pattern and a half of the size of the second patterntherebetween. As an example, the first pattern and the second patternmay be blades having a protruding shape.

When it is assumed that the first pattern unit 21 includes the two firstpatterns having the size of 90° and the second pattern unit 22 includesthe two second patterns having the size of 90°, the plurality of firstpatterns of the first pattern unit 21 and the plurality of secondpatterns of the second pattern unit 22 may be arranged to have an angledifference of 45° therebetween. Therefore, partial regions of theplurality of first patterns of the first pattern unit 21 and theplurality of second patterns of the second pattern unit 22 may overlapeach other in the extending direction of the shaft 11.

In addition, although not illustrated, the first pattern unit 21 mayinclude three first patterns having a size of 60°, and the secondpattern unit 22 may include three second patterns having a size of 60°.However, the first pattern unit 21 and the second pattern unit 22 arenot limited to the example described above, and may include one firstpattern and second pattern or two or more first patterns and secondpatterns, respectively. The plurality of first patterns of the firstpattern unit 21 and the plurality of second patterns of the secondpattern unit 22 may be arranged to have an angle difference of 30°therebetween.

In addition, shapes of the first and second patterns may be rectangularshapes as illustrated in FIG. 1. However, the shapes of the first andsecond patterns are not limited to those illustrated in FIGS. 1 and 2,and may be of many other shapes, such as, for example, circular,elliptical, rhombic, or trapezoidal shapes.

The oscillation circuit 100 may include a plurality of oscillationcircuits. As an example, the oscillation circuit 100 may include a firstoscillation circuit 110 and a second oscillation circuit 120.

The first oscillation circuit 110 may be fixedly mounted on thesubstrate 300 and be spaced apart from the unit 20 to be detected. Thefirst oscillation circuit 110 may include a first sensing coil L10having a first inductance value depending on an overlapping area betweenthe first sensing coil L10 and the first pattern unit 21, and may outputa first sensed oscillation signal LCosc1 based on the first inductancevalue. The second oscillation circuit 120 may be fixedly mounted on thesubstrate 300 and be spaced apart from the unit 20 to be detected. Thesecond oscillation circuit 120 may include a second sensing coil L20having a second inductance value depending on an overlapping areabetween the second sensing coil L20 and the second pattern unit 22, andmay output a second sensed oscillation signal LCosc2 based on the secondinductance value.

As an example, the first oscillation circuit 110 may include a firstcapacitor C10 (FIG. 7) connected to the first sensing coil L10 inparallel to contribute to LC oscillation, and may generate the firstsensed oscillation signal LCosc1. The second oscillation circuit 120(FIG. 7) may include a second capacitor C20 connected to the firstsensing coil L20 in parallel to contribute to LC oscillation, and maygenerate the second sensed oscillation signal LCosc2.

In another example, the first capacitor C10 and the second capacitor 20may be included in the sensing circuit 200. A case in which the firstcapacitor C10 and the second capacitor C20 are included in the first andsecond oscillation circuits 110 and 120, respectively, will hereinafterbe described for convenience of explanation, but the first capacitor C10and the second capacitor C20 are not limited thereto.

The first sensing coil L10 and the second sensing coil L20 may bearranged along the extending direction of the shaft 11. The firstsensing coil L10 may be disposed to face the first pattern unit 21, andthe second sensing coil L20 may be disposed to face the second patternunit 22.

By rotation of the first pattern unit 21 and the second pattern unit 22,an area of the first sensing coil L10 overlapping the first pattern ofthe first pattern unit 21 may be changed, and an area of the secondsensing coil L20 overlapping the second pattern of the second patternunit 22 may be changed. The first and second sensing coils L10 and L20may sense changes in the areas of overlap between the first and secondsensing coils L10 and L20 and the first and second pattern units 21 and22, respectively.

The first sensing coil L10 and the second sensing coil L20 may have asize, which may be determined in advance. In an example, the size of thefirst sensing coil L10 and the second sensing coil L20 may be understoodas a length thereof corresponding to a rotation direction of therotating body. As an example, the size of the first sensing coil L10 andthe second sensing coil L20 may correspond to a half of the size of thefirst pattern of the first pattern unit 21 and the second pattern of thesecond pattern unit 22.

As an example, each of the first sensing coil L10 of the firstoscillation circuit 110 and the second sensing coil L20 of the secondoscillation circuit 120 may be formed of a circuit pattern on thesubstrate 300. In an example, each of the first and second sensing coilsL10 and L20 may be formed of one of a winding-type inductor coil and asolenoid coil. The first and second sensing coils L10 and L20 may sensea rotation angle of the rotating body depending on inductances changeddepending on the areas of overlap between the first and second sensingcoils L10 and L20 and the first and second pattern units 21 and 22,respectively.

In an example, the sensing circuit 200 may be an integrated circuit thatis mounted on the substrate 300, and be electrically connected to thefirst oscillation circuit 110 having the first sensing coil L10 and thesecond oscillation circuit 120 having the second sensing coil L20.

The sensing circuit 200 may output an output signal Sout having movementinformation of the moving body on the basis of each period count valuefor each of the first and second sensed oscillation signals LCosc1 andLCosc2 using one reference oscillation signal OSCref.

For example, the sensing circuit 200 may generate an output signalhaving rotation information including at least one of a rotationdirection, a rotation angle, and an angular velocity of the rotatingbody depending on the changes in the inductances of the first sensingcoil L10 and the second sensing coil L20.

In the drawings figures, an overlapping description for componentsdenoted by the same reference numerals and having the same functions maybe omitted, and contents different from each other in the respectivedrawings will be described.

FIG. 2 is a diagram illustrating an example of a moving body sensingdevice.

Since a moving body sensing device illustrated in FIG. 2 is similar tothat illustrated in FIG. 1, in addition to the description of FIG. 2below, the above descriptions of FIG. 1 are also applicable to FIG. 2,and are incorporated herein by reference. Thus, the above descriptionmay not be repeated here.

Referring to FIG. 2, a rotating body 50 of a moving body sensing devicemay further include a support member 30 connected to the shaft 11.

The support member 30 may be connected to the shaft 11, and may rotateclockwise or counterclockwise around the shaft 11 depending on rotationof the wheel 10. As an example, the support member may be formed in acylindrical shape. The support member 30 may be formed of a non-metalmaterial. As an example, the support member 30 may be formed of plastic.

The unit 20 to be detected may be disposed on the support member 30having the cylindrical shape. The unit 20 to be detected may include afirst pattern unit 21 and a second pattern unit 22 arranged on a sidesurface of the support member 30.

The first pattern unit 21 may include a plurality of first patternsextending from a first height region of the support member 30 formed inthe cylindrical shape along a rotation direction, and the second patternunit 22 may include a plurality of second patterns extending from asecond height region of the support member 30 formed in the cylindricalshape along the rotation direction.

Here, the plurality of first patterns of the first pattern unit 21 andthe plurality of second patterns of the second pattern unit 22 may beformed of one of the metal and the magnetic material.

The support member 30 may be formed of the non-metal material such asthe plastic, and the first pattern unit 21 and the second pattern unit22 may be formed of a metal. The support member 30 may be manufacturedby performing an injection-molding process of the plastic, and the firstpattern unit 21 and the second pattern unit 22 may be formed by aplating process.

The first pattern unit 21 and the second pattern unit 22 may be arrangedon the side surface of the support member 30. When the first patternunit 21 and the second pattern unit 22 are arranged on the supportmember 30, groove portions for providing the first pattern unit 21 andthe second pattern unit 22 may be formed on the side surface of thesupport member 30. As an example, the groove portions may extend alongthe rotation direction in order to form the first pattern unit 21 andthe second pattern unit 22. The first pattern unit 21 and the secondpattern unit 22 may be arranged in the groove portions provided in theside surface of the support member 30, and be externally exposed. As anexample, a thickness of the first pattern unit 21 and the second patternunit 22 may be the same as that of the groove portions. Therefore, astep may not be generated in the side surface of the support member 30by the first pattern unit 21 and the second pattern unit 22 provided inthe groove portions.

The rotating body sensing device illustrated in FIG. 2 may beadvantageous in mass production and cost reduction since thin patternsare manufactured by a method having an excellent mass productionproperty, such as an injection-molding process, a plating process, andlike.

In addition, in relation to each of the first pattern unit 21 and thesecond pattern unit 22, the oscillation circuit 100 may include a firstoscillation circuit 110 having a first sensing coil L10 and a secondoscillation circuit 120 having a second sensing coil L10.

The unit 20 to be detected may include first to N-th pattern units(here, N is a natural number of 3 or more) 21, 22, 23, 24, . . . formedin the moving body to move depending on movement of the moving body andspaced apart from each other.

As an example, a case in which two pattern units are provided will bedescribed with reference to FIG. 3 and a case in which four patternunits are provided will be described with reference to FIG. 4. However,these examples are provided for convenience of explanation andunderstanding, and the number of pattern units is not limited thereto.

FIG. 3 is a diagram illustrating an example of a moving body sensingdevice.

In addition to the description of FIG. 3 below, the above descriptionsof FIGS. 1-2 are also applicable to FIG. 3, and are incorporated hereinby reference. Thus, the above description may not be repeated here.Referring to FIG. 3, an oscillation circuit 100 may include a firstoscillation circuit 110 having a first sensing coil L10, a secondoscillation circuit 120 having a second sensing coil L20, and a thirdoscillation circuit 130 having a third sensing coil L30.

In an example, the third oscillation circuit 130 does not include acorresponding pattern unit, and may thus output a third sensedoscillation signal LCosc3 including noise and based on an inductancevalue. The third sensed oscillation signal LCosc3 may be used as acorrection signal for removing the noise.

FIG. 4 is a diagram illustrating an example of a moving body sensingdevice. In addition to the description of FIG. 4 below, the abovedescriptions of FIGS. 1-3 are also applicable to FIG. 4, and areincorporated herein by reference. Thus, the above description may not berepeated here.

Referring to FIG. 4, a unit 20 to be detected may include a firstpattern unit 21, a second pattern unit 22, a third pattern unit 23, anda fourth pattern unit 24 arranged on a side surface of a support member30 having a cylindrical shape.

In relation to each of the first pattern unit 21, the second patternunit 22, the third pattern unit 23, and the fourth pattern unit 24, anoscillation circuit 100 may include a first oscillation circuit 110having a first sensing coil L10, a second oscillation circuit 120 havinga second sensing coil L20, a third oscillation circuit 130 having athird sensing coil L30, and a fourth oscillation circuit 140 having afourth sensing coil L40.

A case in which two sensing coils are included, a case in which threesensing coils are included, and a case in which four sensing coils areincluded have been described for convenience of explanation in FIGS. 1through 4, but the number of sensing coils is not limited thereto.

In an example, at least two sensing coils may be included. Three sensingcoils may be provided as an example, four sensing coils may be providedas another example, and five sensing coils may be provided as anotherexample.

In addition, the first pattern unit 21 and the second pattern unit 22are not limited to the example illustrated in FIG. 2, and the firstpattern unit 21, the second pattern unit 22, the third pattern unit 23,and the fourth pattern unit 24 are not limited to the exampleillustrated in FIG. 4. In addition, each pattern unit may include onepattern or two or more patterns

In addition, shapes of the first and second patterns may be rectangularshapes as illustrated in FIG. 2. However, the shapes of the first andsecond patterns are not particularly limited to those illustrated inFIG. 2, and may be circular, elliptical, rhombic, trapezoidal shapes, orthe like, in addition to the rectangular shapes.

Meanwhile, the moving body sensing device may use an inductance sensingmanner using a plurality of sensing coils included in the oscillationcircuits. In this case, the moving body sensing device may use a changein an eddy current generated depending on areas of overlap betweeninductances corresponding to the plurality of sensing coils and the unit20 to be detected (a magnetic material or a non-magnetic material) veryclose thereto and measure a change in a frequency due to LC oscillationoutput from the oscillation circuits depending on the change in the eddycurrent to provide sensed data for measuring a rotation amount.

FIG. 5 is a diagram illustrating an example of a sensing circuit of amoving body.

Referring to FIG. 5, a sensing circuit 200 of a moving body may includea frequency divider 210, a period counting circuit unit 220, and acalculation circuit unit 230. The period counting circuit unit 220 mayinclude a first period counting circuit 220-1 and a second periodcounting circuit 220-2.

The frequency divider 210 may divide a frequency of the referenceoscillation signal OSCref and output a frequency-divided referenceoscillation signal DOSCref. As an example, the frequency divider 210 maydivide the frequency of the input reference oscillation signal OSCref bya preset frequency-division number (N) to lower the frequency (forexample, 1 MHz) of the reference oscillation signal OSCref to a lowfrequency (for example, 100 kHz) by the frequency-division number (N),and output the frequency-divided oscillation signal DOSCref.

As an example, the frequency divider 210 may be configured to select thefrequency-division number (N) to obtain a desired frequency resolution,the frequency resolution of the frequency diver 210 may be calculated asthe product (FLCosc*TSN) of a frequency (FLCosc) of an LC oscillationsignal (for example, the lowermost frequency in LCosc1 or LCosc2) and atotal sample number (TSN). Therefore, the higher the frequency (FLCosc)of the LC oscillation signal (the lowermost frequency in LCosc1 orLCosc2 or the larger the total sample number (TSN), the better theresolution.

For example, the frequency (Fosc) of the reference oscillation signalOSCref may be approximately 1 MHz, and the total sample number (TSN) maybe determined as the product of the frequency-division number (N) and anaccumulated gain (GAIN) of the first period counting circuit 220-1 orthe second period counting circuit 220-2. As an example, when thefrequency-division number (N) is 100 and the accumulated gain (GAIN) is256, the total sample number (TSN) may be 25600. In addition, when thefrequency-division number (N) is 100 and the frequency (Fosc) of thereference oscillation signal OSCref is 1 MHz, a frequency (Fosc/N) ofthe frequency-divided reference oscillation signal DOSCref may be 10kHz.

The first period counting circuit 220-1 may generate a first sensedsignal Ssn1 having a first period count value PCV1 counted using thefirst sensed oscillation signal LCosc1 for the frequency-dividedreference oscillation signal DOSCref. The second period counting circuit220-2 may generate a second sensed signal Ssn2 having a second periodcount value PCV2 counted using the second sensed oscillation signalLCosc2 for the frequency-divided reference oscillation signal DOSCref.

As an example, the first period counting circuit 220-1 may include afirst period counter 221-1 and a first filter 222-1.

The first period counter 221-1 may count a period of thefrequency-divided reference oscillation signal DOSCref from thefrequency divider 210 using the first sensed oscillation signal LCosc1to generate the first period count value PCV1 for the frequency-dividedreference oscillation signal DOSCref, and provide the first period countvalue PCV1 to the first filter 222-1.

The first filter 222-1 may amplify the first period count value PCV1from the first period counter 221-1 using a preset accumulated gain(GAIN) to generate a first amplified period count value APCV1, andprovide the first amplified period count value APCV1 as the first sensedsignal Ssn1. In an example, the first filter 222-1 may be a digitalfilter such as, for example, a cascade integrator comb (CIC).

In an example, the first filter 222-1 may determine the accumulated gain(GAIN) on the basis of a preset stage order (SN) and a decimator factor(R). As an example, the first filter 222-1 may determine the accumulatedgain (GAIN) as a multiplier of the stage order (SN) for the decimatorfactor (R).

The second period counting circuit 220-2 may include a second periodcounter 221-2 and a second filter 222-2.

The second period counter 221-2 may count a period of thefrequency-divided reference oscillation signal DOSCref from thefrequency divider 210 using the second sensed oscillation signal LCosc2to generate the second period count value PCV2 for the frequency-dividedreference oscillation signal DOSCref, and provide the second periodcount value PCV2 to the second filter 222-2.

The second filter 222-2 may amplify the second period count value PCV2from the second period counter 221-2 using a preset accumulated gain(GAIN) to generate a second amplified period count value APCV2, andprovide the second amplified period count value APCV2 as the secondsensed signal Ssn2. As an example, the second filter 222-2 may be adigital filter such as, for example, a CIC.

For example, the second filter 222-2 may determine the accumulated gain(GAIN) on the basis of a preset stage order (SN) and a decimator factor(R). As an example, the second filter 222-2 may determine theaccumulated gain (GAIN) as a multiplier of the stage order (SN) for thedecimator factor (R).

The first filter and the second filter described above may primarilyreduce noises by performing a series of accumulation, amplification, andlow pass filtering processes on the period count values.

The calculation circuit unit 230 may calculate the first sensed signalSsn1 and the second sensed signal Ssn2 to generate an output signalSout. As an example, the calculation circuit unit 230 may perform adivision (for example, Ssn1/Ssn2 or Ssn2/Ssn1) on the first sensedsignal Ssn1 and the second sensed signal Ssn2 to generate the outputsignal Sout. In this case, when the division is performed on the firstsensed signal Ssn1 and the second sensed signal Ssn2, noise componentsincluded in each of the first sensed signal Ssn1 and the second sensedsignal Ssn2 may be removed. Further description for this will beprovided below.

In addition, noise components that may be caused by jitter componentsincluded in the reference oscillation signal may be removed through acalculation circuit to secondarily further reduce the noise.

The oscillation circuit 100 may include first to N-th oscillationcircuits 110, 120, 130, 140, . . . fixedly mounted on the substrate 300spaced apart from the unit 20 to be detected, including, respectively,first to N-th sensing coils L10, L20, L30, L40, . . . having first toN-th inductance values depending on areas of overlap between the firstto N-th sensing coils L10, L20, L30, L40, . . . and the first to N-thpattern units 21, 22, 23, 24, . . . , and outputting, respectively,first to N-th sensed oscillation signals LCosc1, LCosc2, LCosc3, LCosc4,. . . based on the first to N-th inductance values.

In addition, the sensing circuit 200 may output an output signal Southaving movement information of the moving body on the basis of eachperiod count value for each of the first to N-th sensed oscillationsignals LCosc1, LCosc2, LCosc3, LCosc4, . . . using one referenceoscillation signal OSCref.

A case in which three oscillation circuits (three sensing coils) areprovided will be described with reference to FIG. 6, and a case in whichfour oscillation circuits (four sensing coils) are provided will bedescribed with reference to FIG. 7. However, these cases are providedfor convenience of explanation and understanding, and the number ofoscillation circuits (sensing coils) are not limited thereto.

FIG. 6 is a diagram illustrating an example of a sensing circuit of amoving body. In addition to the description of FIG. 6 below, the abovedescriptions of FIGS. 1-5 are also applicable to FIG. 6, and areincorporated herein by reference. Thus, the above description may not berepeated here.

Referring to FIG. 6, a sensing circuit 200 of a moving body may includea frequency divider 210, a period counting circuit unit 220, and acalculation circuit unit 230.

The period counting circuit unit 220 may include a first period countingcircuit 220-1, a second period counting circuit 220-2, and a thirdperiod counting circuit 220-3. The calculation circuit unit 230 mayinclude a first calculation circuit 230-1, a second calculation circuit230-2, and a third calculation circuit 230-3.

The sensing circuit 200 of a moving body of FIG. 6 is different fromthat of FIG. 5 in that it further includes the third period countingcircuit 220-3, the first calculation circuit 230-1, the secondcalculation circuit 230-2, and the third calculation circuit 230-3, anda description overlapping that of FIG. 5 will be omitted, and contentsdifferent from those of FIG. 5 will be mainly described.

The third period counting circuit 220-3 may include a third periodcounter 221-3 and a third filter 222-3.

The third period counter 221-3 may count a period of thefrequency-divided reference oscillation signal DOSCref from thefrequency divider 210 using a third sensed oscillation signal LCosc3 togenerate a third period count value PCV3 for each period for thefrequency-divided reference oscillation signal DOSCref, and provide thethird period count value PCV3 to the third filter 222-3.

The third filter 222-3 may amplify the third period count value PCV3from the third period counter 221-3 using a preset accumulated gain(GAIN) to output a third amplified period count value APCV3, and providethe third amplified period count value APCV3 as a third sensed signalSsn3. As an example, the third filter 222-3 may be a digital filter suchas, for example, a CIC.

For example, the third filter 222-3 may determine the accumulated gain(GAIN) on the basis of a preset stage order (SN) and a decimator factor(R). As an example, the third filter 222-3 may determine the accumulatedgain (GAIN) as a multiplier of the stage order (SN) for the decimatorfactor (R).

The first calculation circuit 230-1 may calculate the first sensedsignal Ssn1 and the third sensed signal Ssn3 to generate a firstcalculated signal Sca1. As an example, the first calculation circuit230-1 may perform a subtraction on the first sensed signal Ssn1 and thethird sensed signal Ssn3 to generate the first calculated signal Sca1.In this case, when the subtraction is performed on the first sensedsignal Ssn1 and the third sensed signal Ssn3, noise included in thefirst sensed signal Ssn1 may be removed by noise included in the thirdsensed signal Ssn3. Further description for this will be provided below.

In addition, the second calculation circuit 230-2 may calculate thesecond sensed signal Ssn2 and the third sensed signal Ssn3 to generate asecond calculated signal Sca2. As an example, the second calculationcircuit 230-2 may perform a subtraction on the second sensed signal Ssn2and the third sensed signal Ssn3 to generate the second calculatedsignal Sca2. In this case, when the subtraction is performed on thesecond sensed signal Ssn2 and the third sensed signal Ssn3, noiseincluded in the second sensed signal Ssn2 may be removed by noiseincluded in the third sensed signal Ssn3. Further description for thiswill be provided below.

The third calculation circuit 230-3 may generate an output signal Soutusing the first calculated signal Sca1 and the second calculated signalSca2.

FIG. 7 is a diagram illustrating an example of a sensing circuit of amoving body. In addition to the description of FIG. 7 below, the abovedescriptions of FIGS. 1-6 are also applicable to FIG. 7, and areincorporated herein by reference. Thus, the above description may not berepeated here.

Referring to FIG. 7, the oscillation circuit 100 may include first tofourth oscillation circuits 110 to 140.

The first oscillation circuit 110 may include a first capacitor C10connected to a first sensing coil L10 in parallel to contribute LCoscillation and generate a first sensed oscillation signal LCosc1, thesecond oscillation circuit 120 may include a second capacitor C20connected to a second sensing coil L20 in parallel to contribute LCoscillation and generate a second sensed oscillation signal LCosc2, thethird oscillation circuit 130 may include a third capacitor C30connected to a third sensing coil L30 in parallel to contribute LCoscillation and generate a third sensed oscillation signal LCosc3, andthe fourth oscillation circuit 140 may include a fourth capacitor C40connected to a fourth sensing coil L40 in parallel to contribute LCoscillation and generate a fourth sensed oscillation signal LCosc4.

The period counting circuit unit 220 may include first to fourth periodcounting circuits 220-1 to 220-4 generating, respectively, first tofourth sensed signals having first to fourth period count values countedusing the frequency-divided reference oscillation signal DOSCref foreach of the first to fourth sensed oscillation signals.

The calculation circuit unit 230 may calculate the first to fourthsensed signal to generate first and second calculated signal Sca1 andSca2, and may output an output signal Sout using the first and secondcalculated signals Sca1 and Sca2. As an example, the calculation circuitunit 230 may include a first calculation circuit 230-1, a secondcalculation circuit 230-2, and a third calculation circuit 230-3.

The sensing circuit 200 of a moving body of FIG. 7 is different fromthat of FIG. 6 in that it further includes the fourth oscillationcircuit 140 and the fourth period counting circuit 220-4 and calculationfunctions of the first calculation circuit 230-1, the second calculationcircuit 230-2, and the third calculation circuit 230-3 are differentfrom those of the first calculation circuit 230-1, the secondcalculation circuit 230-2, and the third calculation circuit 230-3 ofFIG. 6, and a description overlapping that of FIG. 6 will be omitted,and contents different from those of FIG. 6 will be mainly described.

The fourth oscillation circuit 140 may include the fourth capacitor C40connected to the fourth sensing coil L40 in parallel to contribute theLC oscillation, and generate the fourth sensed oscillation signalLCosc4.

The fourth period counting circuit 220-4 may include a fourth periodcounter 221-4 and a fourth filter 222-4.

The fourth period counter 221-4 may count a period of thefrequency-divided reference oscillation signal DOSCref from thefrequency divider 210 using the fourth sensed oscillation signal LCosc4to generate a fourth period count value PCV4 for each period for thefrequency-divided reference oscillation signal DOSCref, and provide thefourth period count value PCV4 to the fourth filter 222-4.

The fourth filter 222-4 may amplify the fourth period count value PCV4from the fourth period counter 221-4 using a preset accumulated gain(GAIN) to output a fourth amplified period count value APCV4, andprovide the fourth amplified period count value APCV4 as a fourth sensedsignal Ssn4. As an example, the fourth filter 222-4 may be a digitalfilter such as, for example a CIC.

For example, the fourth filter 222-4 may determine the accumulated gain(GAIN) on the basis of a preset stage order (SN) and a decimator factor(R). As an example, the fourth filter 222-4 may determine theaccumulated gain (GAIN) as a multiplier of the stage order (SN) for thedecimator factor (R).

The first calculation circuit 230-1 may generate a first calculatedsignal Sca1 using the first to fourth sensed signals Ssn1 to Ssn4. Thesecond calculation circuit 230-2 may generate a second calculated signalSca2 using the first to fourth sensed signals Ssn1 to Ssn4. The thirdcalculation circuit 230-3 may generate an output signal Sout using thefirst calculated signal Sca1 and the second calculated signal Sca2.

For example, in FIG. 7, the first calculated signal Sca1, the secondSca2, and the output signal Sout may be calculated as represented by thefollowing Equation 1:

Sca1=(Ssn1−Ssn3)/(2*MAX(Ssn1,Ssn2,Ssn3,Ssn4)−(Ssn1+Ssn3))

Sca2=(Ssn2−Ssn4)/(2*MAX(Ssn1,Ssn2,Ssn3,Ssn4)−(Ssn2+Ssn4))

Sout=Sca1−Sca2.  [Equation 1]

Here, MAX( ) refers to a signal having the largest level among signalsin parentheses.

FIG. 8 is a diagram illustrating examples of a reference oscillationsignal, a frequency-divided reference oscillation signal, and detectedfirst and second oscillation signals.

In FIG. 8, OSCref refers to the reference oscillation signal input tothe frequency divider 210, and a frequency of the reference oscillationsignal OSCref may be 1 MHz as an example. DOSCref refers to thefrequency-divided reference oscillation signal output from the frequencydivider 210, and a frequency of the frequency-divided referenceoscillation signal DOCSref may be 100 kHz as an example. LCosc1 refersto the first sensed oscillation signal, and a frequency of the firstsensed oscillation signal LCosc1 may be 15 MHz as an example. Inaddition, LCosc2 refers to the second sensed oscillation signal, and afrequency of the second sensed oscillation signal LCosc2 may be 30 MHzas an example.

FIG. 9 is a diagram illustrating examples of a reference oscillationsignal, a frequency-divided reference oscillation signal, and detectedfirst to third oscillation signals.

In FIG. 9, LCosc1 refers to the first sensed oscillation signal, and afrequency of the first sensed oscillation signal LCosc1 may be 15 MHz asan example. LCosc2 refers to the second sensed oscillation signal, and afrequency of the second sensed oscillation signal LCosc2 may be 30 MHzas an example. In addition, LCosc3 refers to the third sensedoscillation signal, and a frequency of the third sensed oscillationsignal LCosc3 may be 20 MHz as an example.

FIG. 10 is a diagram illustrating examples of a reference oscillationsignal, a frequency-divided reference oscillation signal, and detectedfirst to fourth oscillation signals.

In FIG. 10, LCosc1 refers to the first sensed oscillation signal, and afrequency of the first sensed oscillation signal LCosc1 may be 15 MHz asan example. LCosc2 refers to the second sensed oscillation signal, and afrequency of the second sensed oscillation signal LCosc2 may be 30 MHzas an example. LCosc3 refers to the third sensed oscillation signal, anda frequency of the third sensed oscillation signal LCosc3 may be 20 MHzas an example. In addition, LCosc4 refers to the fourth sensedoscillation signal, and a frequency of the fourth sensed oscillationsignal LCosc4 may be 35 MHz as an example.

In an example, a manner of counting the frequency-divided referenceoscillation signal DOSCref using the sensed oscillation signals such asthe first to fourth sensed oscillation signals LCosc1 to LCosc4, and thelike, may be used unlike a manner of counting a frequency-divided sensedsignal using a reference clock. In an example, the reference oscillationsignal OSCref having a relatively low frequency may be used, and powerconsumption may thus be reduced.

FIG. 11 is a diagram illustrating an example of a first filter.

Referring to FIG. 11, as an example, the first filter 222-1 may includea decimator CIC filter 222F, and may optionally include a moving averagefilter 222M.

The decimator CIC filter 222F may amplify the first frequency countvalue PCV1 from the first period counter 221-1 with the accumulated gaindetermined on the basis of the stage order (SN) and the decimator factor(R) and provide the first amplified period counter value APCV1.

The moving average filter 222M may calculate a moving average value forthe first amplified period counter value APCV1 from the decimator CICfilter 222F and provide the moving average value for the first amplifiedperiod counter value APCV1 as the first sensed signal Ssn1.

For example, when the first filter 222-1 does not include the movingaverage filter 222M, the first sensed signal Ssn1 may be the firstamplified period counter value APCV1. In another example, when the firstfilter 222-1 does not include the moving average filter 222M, the firstsensed signal Ssn1 may be the moving average value for the firstamplified period counter value APCV1.

In an example, the decimator CIC filter 222F may include an integrationcircuit 222F-1, a decimator 222F-2, and a comb circuit 222F-3.

The integration circuit 222F-1 may include a plurality of integrators Icascaded by the number corresponding to the stage order (SN),sequentially accumulate the first frequency count value PCV1 from thefirst period counter 221-1, and provide accumulated values for eachperiod.

The decimator 222F-2 may sample the accumulated values for each periodfrom the integration circuit 222F-1 one by one for each periodcorresponding to the decimator factor (R) and provide a downsampledaccumulated value.

The comb circuit 222F-3 may include a plurality of combs C cascaded bythe number corresponding to the stage order (SN), subtract the previousdownsampled accumulated value from a current downsampled accumulatedvalue from the decimator 222F-2, and provide a subtracted accumulatedvalue for a period corresponding to the decimator factor (R).

As an example, when the stage order (SN) is quaternary, the decimatorfactor (R) is 1, and a comb differential delay M is 4, the decimator CICfilter 222F may be a 4 stage 4 decimator CIC digital filter. In thisexample, the accumulated gain (GAIN) may be 256[(R*M)^(SN)=(1*4)⁴]corresponding 4⁴. Here, the stage order (SN), the decimator factor (R),and the comb differential delay M are only examples, and are not limitedthereto.

As an example, the integration circuit 222F-1 may include fourintegrators I, sequentially accumulate the first frequency period countvalue PCV1 from the first period counter 221-1 and a fourth perioddelayed value, and provide accumulated values for each period. As anexample, the integration circuit 222F-1 may include the four integratorsI.

The decimator 222F-2 may sample the accumulated values for each periodfrom the integration circuit 222F-1 one by one for every four periodscorresponding to the decimator factor (R=4) and provide a ¼ downsampledaccumulated value. As an example, the comb circuit 222F-3 may includefour combs C.

As an example, in the first filter 222-1, as described above, when thefirst period count value PCV1 is 49 and the accumulated gain (GAIN) is256, the first amplified period count value APCV1 may be 49*256(=12544),which is the product of the first period count value PCV1 of 49 and theaccumulated gain (GAIN) of 256. That is, the first filter 222F-1 mayamplify the first period count value PCV1 for the frequency-dividedreference oscillation signal generated by dividing the frequency of theinput reference oscillation signal using the first accumulated gain(GAIN) to achieve an effect of obtaining a large sample number eventhough a small frequency-division number is used.

Referring to FIG. 11, as an example, when the moving average filter 222Mis a 16-moving average filter, the moving average filter 222M maycalculate a moving average value for the frequency value from thedecimator CIC filter 222F in 16 units and provide the moving averagevalue for the first amplified period count value as the first sensedsignal Ssn1.

For example, the 16-moving average filter 222M may calculate an averagefor 16 data of the output value of the 4 stage 4 decimator CIC filter222F while taking moving sum for the 16 data, thereby serving tostabilize a fluctuation of a measured frequency value. As an example,the moving average filter 222M may be a half band digital filter, or thelike.

Referring to FIG. 5, in the moving body sensing device a periodcomponent and a jitter noise of a reference oscillation frequencyReference OSC may be removed, and the output signal Sout may becalculated as represented by the following Equation 2 and Equation 3 onthe basis of the following examples (1) to (8):

(1) Period of Reference Oscillation Frequency Reference OSC: Tref

(2) Period of First Sensed Oscillation Signal LCosc1: Tlc1

(3) Period of Second Sensed Oscillation Signal LCosc2: Tlc2

(4) Jitter of Reference Oscillation Signal OSCref: delta

(5) Frequency-Division Number of Reference Oscillation Signal OSCref: N

(6) Gain of First and Second Filters: G

(7) Ssn1: Digital Code Value Output from First Filter

(8) Ssn2: Digital Code Value Output from Second Filter

Sout=Ssn1/Ssn2.  [Equation 2]

When it is assumed that a jitter of each of the first sensed oscillationsignal LCosc1 and the second sensed oscillation signal LCosc2 is notpresent and an effect of a low pass filter is ignored in order tosimplify calculation of the above Equation 2, the above Equation 2 maybe represented by the following Equation 3:

$\begin{matrix}{{{{Ssn}\; 1} = {\left( {G^{*}{N^{*}\left( {{Tref} + {delta}} \right)}} \right)\text{/}\left( {{Tlc}\; 1} \right)}}{{{Ssn}\; 2} = {\left( {G^{*}{N^{*}\left( {{Tref} + {delta}} \right)}} \right)\text{/}\left( {{Tlc}\; 2} \right)}}\begin{matrix}{{Sout} =} & {{{Ssn}\; 1\text{/}{Ssn}\; 2} = {\left\lbrack {\left( {G^{*}{N^{*}\left( {{Tref} + {delta}} \right)}} \right)\text{/}\left( {{Tlc}\; 1} \right)} \right\rbrack*}} \\ & {\left\lbrack {\left( {{Tlc}\; 2} \right)\text{/}\left( {G^{*}{N^{*}\left( {{Tref} + {delta}} \right)}} \right\rbrack} \right.} \\{=} & {\left( {{Tlc}\; 2} \right)\text{/}\left( {{Tlc}\; 1} \right)}\end{matrix}} & \left\lbrack {{Equation}\mspace{14mu} 3} \right\rbrack\end{matrix}$

It may be seen from the above Equations 2 and 3 that delta, a jittercomponent generating noise, is removed in the output signal Sout outputfrom the moving body sensing device.

Therefore, the moving body sensing device according to the presentdisclosure reduces the noise caused by the jitter.

For example, referring to FIGS. 5 and 11, the output signal Sout may becalculated as represented by the following Equation 4 in the followingconditions (1) to (6) on the assumption that frequency characteristicsof the first and second oscillation signals Losc1 and Losc2 are changedas follows depending on a position of a magnetic material or anon-magnetic material that is to be sensed by the first and secondsensing coils L10 and L20:

(1) Frequency Reference OSC of Reference Oscillation Signal=1 MHz

(2) Frequency of First Sensed Signal LSosc1=30 to 31 MHz

(3) Frequency of Second Sensed Signal LSosc2=21 to 20 MHz (It is assumedthat a frequency of the second sensed signal is decreased when the firstsensed signal LCosc1 is increased)

(4) Frequency-Division Number of Frequency Reference OSC of ReferenceOscillation Signal: 128

(5) Gain (Gain) of First Filter (4 stage 4 decimator CIC Filter):256*((RM)SN (R: decimator factor, M: comb differential delay, SN=stage))

(6) Assuming that a numerator is multiplied by 216 in order to performdigital integer calculation in a calculation circuit

Sout=(216)*[Ssn1/Ssn2]

Ssn1=256*128*30 MHz/1 MHz to 256*128*31 MHz/1 MHz=983040 to 1015808

Ssn2=256*128*21 MHz/1 MHz to 256*128*20 MHz/1 MHz=688128 to 655360

Sout(Digital output)=93622 to 101580=>7957 Code Change Amount  [Equation4]

Referring to the above Equation 4, it may be applied to methods such asposition control of a motor, position control of an actuator, distancesensing, and the like, depending on a code change amount of the outputsignal Sout (digital output).

In the example described above, the calculation circuit unit 230 of FIG.5 may perform the division on the first sensed signal Ssn1 and thesecond sensed signal Ssn2 to generate the output signal Sout.

In this regard, a series of arithmetic operations of the first sensedsignal Ssn1 and the second sensed signal Ssn2 may be applied before andafter the division of the calculation circuit unit 230. For example, anoperation of (SENSING1−SENSING2)/(SENSING1+SENSING2) may be performed.

Therefore, it may be seen that a component of Tref+delta is offset whenthe division is performed after the series of arithmetic operations asdescribed above in Equations.

FIG. 12 is a diagram illustrating an example of a second filter, andFIG. 13 is a diagram illustrating an example of a third filter. Inaddition, FIG. 14 is a diagram illustrating an example of a fourthfilter.

Referring to FIG. 12, the second filter 222-2 may include a decimatorCIC filter 222F, and may optionally include a moving average filter222M.

Referring to FIG. 13, the third filter 222-3 may include a decimator CICfilter 222F, and may optionally include a moving average filter 222M.

Referring to FIG. 14, the fourth filter 222-4 may include a decimatorCIC filter 222F, and may optionally include a moving average filter222M.

Operations of each of the second filter 222-1 of FIG. 12, the thirdfilter 222-3 of FIG. 13, and the fourth filter 222-4 of FIG. 14 aresubstantially the same as those of the first filter 222-1 illustrated inFIG. 11, thus, in addition to the description of FIGS. 12-14 below, theabove descriptions of FIG. 11 are also applicable to FIGS. 12-14, andare incorporated herein by reference. Thus, the above description maynot be repeated here.

FIG. 15 is a diagram for describing a positional relationship between aunit to be detected and a sensing coil depending on rotation of the unitto be detected. FIG. 16 is a diagram illustrating examples of waveformsof a first sensed signal and a second sensed signal output from a periodcounting circuit and an output signal.

In FIGS. 15 and 16, the first sensing coil L10 and the second sensingcoil L20 are illustrated as pattern coils, which are examples of thefirst sensing coil L10 and the second sensing coil L20.

Referring to FIGS. 15 and 16, areas of overlap between the unit 20 to bedetected and the first and second sensing coils L10 and 20 may bechanged by rotation of the wheel 10. In detail, an overlapping areabetween the first pattern unit 21 and the first sensing coil L10 and anoverlapping area between the second pattern unit 22 and the secondsensing coil L20 may be changed. In FIG. 15, it is assumed that thefirst pattern unit 21 and the second pattern unit 22 rotates from thebottom toward the top.

In a first state State 1, the first sensing coil L10 may overlap thefirst pattern unit 21, and the second sensing coil L20 may not overlapthe second pattern unit 22. When a pattern formed of a metal material isadjacent to the first sensing coil L10 formed of a sensing coil, acurrent may be applied to the pattern by a magnetic flux generated inthe sensing coil, and a magnetic flux may be generated in the pattern bythe current applied to the pattern. In this case, the magnetic fluxgenerated in the pattern may increase an inductance of the sensing coilof the first sensing coil L10 by a skin effect. Therefore, referring to270° or 90° of a first state State 1 of FIG. 6 corresponding to thefirst state State 1 (the first pattern unit and the second pattern unitmove from 360° toward 0° in FIG. 16), the first sensed signal Ssn1 maybe maintained at a low level in inverse proportion to the inductance,while the second sensed signal Ssn2 of the second sensing coil L20 maybe maintained at a high level.

After the first state State 1, the first pattern unit 21 and the secondpattern unit 22 may rotate from the bottom toward the top, such that ina second state State 2, the first sensing coil L10 may overlap the firstpattern unit 21, and the second sensing coil L20 may overlap the secondpattern unit 22. Therefore, referring to 225° and 45° of FIG. 16corresponding to the second state State 2, the first sensed signal Ssn1of the first sensing coil L10 may be maintained at the low level ininverse proportion to the inductance, while a level of the second sensedsignal Ssn2 of the second sensing coil L20 may be changed into a lowlevel.

After the second state State 2, the first pattern unit 21 and the secondpattern unit 22 may rotate from the bottom toward the top, such that ina third state State 3, the first sensing coil L10 may not overlap thefirst pattern unit 21, and the second sensing coil L20 may overlap thesecond pattern unit 22. Therefore, referring to 180° or 0° of FIG. 16corresponding to the third state State 3, a level of the first sensedsignal Ssn1 of the first sensing coil L10 may be changed into a highlevel, while the second sensed signal Ssn2 of the second sensing coilL20 may be maintained at the low level.

After the third state State 3, the first pattern unit 21 and the secondpattern unit 22 may rotate from the bottom toward the top, such that ina fourth state State 4, the first sensing coil L10 may not overlap thefirst pattern unit 21, and the second sensing coil L20 may not overlapthe second pattern unit 22. Therefore, referring to 135° or 315° of FIG.16 corresponding to the fourth state State 4, the first sensed signalSsn1 of the first sensing coil L10 may be at the high level, and a levelof the second sensed signal Ssn2 of the second sensing coil L20 may bechanged into a high level.

In FIGS. 15 and 16, as an example, the output signal Sout may be asignal obtained by dividing (Ssn2/Ssn1) the second sensed signal Ssn2 bythe first sensed signal Ssn1, but is not limited thereto.

FIG. 17 a diagram for describing a positional relationship between aunit to be detected and a sensing coil depending on rotation of the unitto be detected. FIG. 18 is a diagram illustrating a state relationshipbetween first to fourth sensed signals output from the period countingcircuit, first and second calculated signals, and an output signal.

Referring to FIGS. 4, 7, 17, and 18, in a first state State 1, the firstand fourth sensing coils L10 and L40 may overlap the first and fourthpattern units 21 and 24, respectively, and the second and third sensingcoils L20 and L30 may not overlap the second and third sensing units 22and 23, respectively. In this case, large inductance values may begenerated depending on magnetic fluxes by currents applied tocorresponding patterns in the first and fourth sensing coils L10 and L40overlapping the first and fourth pattern units 21 and 24, respectively,and small inductance values may be generated in the second and thirdsensing coils L20 and L30 that do not overlap the second and thirdpattern units 22 and 23, respectively. Therefore, as illustrated in FIG.18, since an inductance value and a signal level are opposite to eachother, the second and third sensed signals Ssn2 and Ssn3 may behigh-level signals, and the first and fourth sensed signals Ssn1 andSsn4 may be low-level signals.

In a second state State 2, after the first state State 1, the respectivepattern units rotate, such that the first and second sensing coils L10and L20 may overlap the first and second pattern units 21 and 22,respectively, and the third and fourth sensing coils L30 and L40 may notoverlap the third and fourth sensing units 23 and 24, respectively. Inthis case, large inductance values may be generated depending onmagnetic fluxes by currents applied to corresponding patterns in thefirst and second sensing coils L10 and L20 overlapping the first andsecond pattern units 21 and 22, respectively, and small inductancevalues may be generated in the third and fourth sensing coils L30 andL40 that do not overlap the third and fourth pattern units 23 and 24,respectively. Therefore, as illustrated in FIG. 18, since an inductancevalue and a signal level are opposite to each other, the third andfourth sensed signals Ssn3 and Ssn4 may be high-level signals, and thefirst and second sensed signals Ssn1 and Ssn2 may be low-level signals.

In a third state State 3, after the second state State 2, the respectivepattern units rotate, such that the second and third sensing coils L20and L30 may overlap the second and third pattern units 22 and 23,respectively, and the first and fourth sensing coils L10 and L40 may notoverlap the first and fourth sensing units 21 and 24, respectively. Inthis case, large inductance values may be generated depending onmagnetic fluxes by currents applied to corresponding patterns in thesecond and third sensing coils L20 and L30 overlapping the second andthird pattern units 22 and 23, respectively, and small inductance valuesmay be generated in the first and fourth sensing coils L10 and L40 thatdo not overlap the first and fourth pattern units 21 and 24,respectively. Therefore, as illustrated in FIG. 18, since an inductancevalue and a signal level are opposite to each other, the first andfourth sensed signals Ssn1 and Ssn4 may be high-level signals, and thesecond and third sensed signals Ssn2 and Ssn3 may be low-level signals.

In addition, in a fourth state State 4, after the third state State 3,the respective pattern units rotate, such that the third and fourthsensing coils L30 and L40 may overlap the third and fourth pattern units23 and 24, respectively, and the first and second sensing coils L10 andL20 may not overlap the first and second pattern units 21 and 22,respectively. In this case, large inductance values may be generateddepending on magnetic fluxes by currents applied to correspondingpatterns in the third and fourth sensing coils L30 and L40 overlappingthe third and fourth pattern units 23 and 24, respectively, and smallinductance values may be generated in the first and second sensing coilsL10 and L20 that do not overlap the first and second pattern units 21and 22, respectively. Therefore, as illustrated in FIG. 18, since aninductance value and a signal level are opposite to each other, thefirst and second sensed signals Ssn1 and Ssn2 may be high-level signals,and the third and fourth sensed signals Ssn3 and Ssn4 may be low-levelsignals.

FIG. 19 is a graph illustrating an example of noise included in anoutput signal of a sensing device. The graph illustrated in FIG. 19 is agraph illustrating a magnitude Vpp of noise included in an output signalin a case in which a sensing device uses a manner of counting afrequency-divided sensed signal using a reference clock and uses onesensing coil.

FIG. 20 is a graph illustrating an example of noise included in anoutput signal of the moving body sensing device according to theembodiments described above-. The graph illustrated in FIG. 20 is agraph illustrating a magnitude Vpp of noise included in the outputsignal of the moving body sensing device according to the presentdisclosure.

Graphs of FIGS. 19 and 20 are graphs illustrating measurement results ina case in which a Reference OSC is 10 MHz at the time of injecting noiseof 10 to 9.8 MHz at a rate of 1 kHz into the reference oscillationfrequency Reference OSC in a frequency shift keying (FSK) manner.

In the graphs of FIGS. 19 and 20, a vertical axis is a voltage axis (V),and a horizontal axis is a time axis (msec). When comparing themagnitude of the noise of FIG. 19 and the magnitude of the noise of FIG.20 with each other, it may be seen that the magnitude of the noiseincluded in the output signal of the moving body sensing deviceaccording to the present disclosure is relatively smaller.

The moving body sensing device according to the present disclosure asdescribed above may be used in an actuator module of a camera. In thiscase, a position of the actuator module may be controlled by measuring achange in a frequency depending on a change in a position between amagnet which is the unit to be detected and the sensing coil.Alternatively, control and post-processing may be performed by sensing aposition of a motor or an encoder of a rotating body.

In addition, a phase locked loop for generating a reference oscillationfrequency Reference OSC that is high and has a low noise or a lowdrop-out (LDD) regulator for supplying a precise voltage has beenrequired in the related art, but a manner according to the presentdisclosure may be used to reduce a size of an integrated circuit (IC),and lower a reference oscillation frequency Reference OSC, therebyimplementing a low power circuit.

In addition, an inductance sensing manner robust to a jitter noise ofthe reference oscillation frequency Reference OSC may be realized.

As set forth above, a sensing circuit of a moving body and a moving bodysensing device in which a reference oscillation signal having arelatively low frequency may be used to reduce power consumption and atleast two sensed signals may be used to be robust to noise due to ajitter may be provided.

Therefore, the sensing circuit of a moving body and the moving bodysensing device may be operated at a lower power, the noise such as thejitter may be efficiently reduced, and an influence of the noise may bereduced. As a result, a fine displacement of a rotating body may be moreprecisely sensed.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents. Therefore, the scope of the disclosure is defined not bythe detailed description, but by the claims and their equivalents, andall variations within the scope of the claims and their equivalents areto be construed as being included in the disclosure.

What is claimed is:
 1. A sensing circuit in a device having a movingbody in which a unit to be detected comprising first and second patternunits spaced apart from each other is provided, comprising: anoscillation circuit unit comprising first and second sensing coilsfixedly mounted on a substrate spaced apart from the unit to bedetected, the first and second sensing coils having first and secondinductance values depending on areas of overlap between the first andsecond sensing coils and the first and second pattern units, andconfigured to output first and second sensed oscillation signals basedon the first and second inductance values; and a sensing circuitconfigured to count each of the first and second sensing oscillationsignals using a reference oscillation signal to obtain first and secondperiod count values, and calculates the first and second period countvalues to output an output signal having movement information of themoving body.
 2. The sensing circuit of claim 1, the oscillation circuitunit comprising: a first oscillation circuit comprising a firstcapacitor connected to the first sensing coil in parallel to contributeto LC oscillation and to generate the first sensed oscillation signal,and a second oscillation circuit comprising a second capacitor connectedto the second sensing coil in parallel to contribute LC oscillation andto generate the second sensed oscillation signal.
 3. The sensing circuitof claim 2, wherein the sensing circuit comprises: a frequency dividerconfigured to divide a frequency of the reference oscillation signal andto output a frequency-divided reference oscillation signal; a periodcounting circuit unit comprising first and second period countingcircuits configured to generate, respectively, the first and secondsensed signals having first and second period count values counted usingthe frequency-divided reference oscillation signal for each of the firstand second sensed oscillation signals; and a calculation circuit unitconfigured to calculate the first and second sensed signals to generatethe output signal.
 4. The sensing circuit of claim 3, wherein the firstperiod counting circuit comprises: a first period counter configured tocount a period of the frequency-divided reference oscillation signalusing the first sensed oscillation signal to generate a first periodcount value for the frequency-divided reference oscillation signal; anda first filter configured to amplify the first period count value usingan accumulated gain to generate a first amplified period count value andto provide the first amplified period count value as the first sensedsignal.
 5. The sensing circuit of claim 4, wherein the second periodcounting circuit comprises: a second period counter configured to counta period of the frequency-divided reference oscillation signal using thesecond sensed oscillation signal to generate a second period count valuefor the frequency-divided reference oscillation signal; and a secondfilter configured to amplify the second period count value using anaccumulated gain to generate a second amplified period count value andto provide the second amplified period count value as the second sensedsignal.
 6. The sensing circuit of claim 5, wherein the first and secondfilters are configured to determine the accumulated gain using a presetstage order and a decimator factor.
 7. The sensing circuit of claim 6,wherein the first and second filters are configured to determine theaccumulated gain as a multiplier of the stage order for the decimatorfactor.
 8. The sensing circuit of claim 7, wherein the calculationcircuit unit is configured to perform a division on the first sensedsignal and the second sensed signal to generate the output signal.
 9. Amoving body sensing device comprising: a unit to be detected configuredto be disposed in a moving body to move based on movement of the movingbody and to comprise first to N-th pattern units spaced apart from eachother; an oscillation circuit unit comprising first to N-th sensingcoils fixedly mounted on a substrate spaced apart from the unit to bedetected, the first to N-th sensing coils having first to N-thinductance values depending on areas of overlap between the first toN-th sensing coils and the first to N-th pattern units, and configuredto output first to N-th sensed oscillation signals based on the first toN-th inductance values; and a sensing circuit configured to count eachof the first to Nth sensing oscillation signals using a referenceoscillation signal to obtain first to Nth period count values, andcalculates the first to Nth period count values to output an outputsignal having movement information of the moving body, wherein N is anatural number of 3 or more.
 10. The moving body sensing device of claim9, wherein the first to N-th pattern units are formed of any one of ametal and a magnetic material having a same shape.
 11. The moving bodysensing device of claim 10, wherein the oscillation circuit unitcomprises a first oscillation circuit, a second oscillation circuit, athird oscillation circuit, and fourth to Nth oscillation circuits, thefirst oscillation circuit comprising a first capacitor connected to thefirst sensing coil in parallel to contribute LC oscillation and togenerate the first sensed oscillation signal, the second oscillationcircuit comprising a second capacitor connected to the second sensingcoil in parallel to contribute LC oscillation and to generate the secondsensed oscillation signal, the third oscillation circuit comprising athird capacitor connected to the third sensing coil in parallel tocontribute LC oscillation and to generate the third sensed oscillationsignal, and the fourth oscillation circuit comprising a fourth capacitorconnected to the fourth sensing coil in parallel to contribute LCoscillation and to generate the fourth sensed oscillation signal. 12.The moving body sensing device of claim 11, wherein the sensing circuitcomprises: a frequency divider configured to divide a frequency of thereference oscillation signal and to output a frequency-divided referenceoscillation signal; a period counting circuit unit comprising first tofourth period counting circuits generating, respectively, the first tofourth sensed signals having first to fourth period count values countedusing the frequency-divided reference oscillation signal for each of thefirst to fourth sensed oscillation signals; and a calculation circuitunit configured to calculate the first to fourth sensed signals togenerate first and second calculated signals and to output the outputsignal using the first and second calculated signals.
 13. The movingbody sensing device of claim 12, wherein the first to fourth periodcounting circuits comprise, respectively, first to fourth periodcounters configured to count a period of the frequency-divided referenceoscillation signal using the first to fourth sensed oscillation signals,respectively, to generate the first to fourth period count values forthe frequency-divided reference oscillation signal; and first to fourthfilters configured to amplify the first to fourth period count valuesusing accumulated gain to generate first to fourth amplified periodcount values and to provide the first to fourth amplified period countvalues as the first to fourth sensed signals.
 14. The moving bodysensing device of claim 13, wherein the first to fourth filters areconfigured to determine the accumulated gain using a preset stage orderand a decimator factor.
 15. The moving body sensing device of claim 14,wherein the first to fourth filters are configured to determine theaccumulated gain as a multiplier of the stage order for the decimatorfactor.
 16. The moving body sensing device of claim 15, wherein thecalculation circuit unit comprises: a first calculation circuitconfigured to generate the first calculated signal using the first tofourth sensed signals; a second calculation circuit configured togenerate the second calculated signal using the first to fourth sensedsignals; and a third calculation circuit configured to generate theoutput signal using the first and second calculated signals.